Traditionally ripple control has been used to transmit information from a power source to a load via the power transmission system to afford remote control of that load. The most common use is in the control of the heating of hot water.
At present, ripple signal receivers are limited to direct control applications wherein they recognise a predetermined signal and execute a predetermined function. They are not capable of recognising more than one input or executing more than one function or set of functions based on the information contained in the inputs. Furthermore, the signal recognition and output function parameters are either limited or set at the time of manufacture so that each receiver is designed and manufactured for a specific purpose.
Currently available receivers are also traditionally associated with or attached to the main switchboard of a building or dwelling, from which a dedicated circuit is wired to the electrical appliance of which the receiver is the controller. The currently available receivers are also unable to decode the ripple signal and transmit the information contained in the signal to other devices.
EP 0159896 discloses a ripple control system wherein the receiver uses a pair of synchronous filters driven 90.degree. out of phase with each other to reject unwanted signals. The emphasis of the invention is on obtaining narrow bandwidth analogue filtering to enable the recognition of a predetermined code which may incorporate more than one frequency. The receiver then executes a predetermined function.
Other ripple receivers are known and include Aust 26102/71 and Aust 45281/79. However those are dedicated to receiving a particular ripple signal and executing a predetermined function or set of functions in response to that code.
NZ 211797, NZ 216945, and NZ 172898 disclose inventions relating to analogue or digital filtering of a wanted ripple signal in a ripple receiver. The inventions emphasise the filtering of a wanted ripple signal and do not disclose a selection of output functions which are dependent on one or more received ripple signals.